Tuesday, 15 October 2013

Ibanez BS10 Bass Stack

There you go John. We'll never have enough bass designs... This one is basically a Rat for bass.

Thanks to John, this one is now verified. Which also means that the LM7 and FC10 should be safe to build.



19 comments:

  1. coolio! thanks Miro!
    I plan to start building it tonight.

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  2. built it. I checked everything multiple times (components, traces, cuts, solder bridges etc) and it doesn't work. maybe i'm blind but I don't see where Vref1 is on your layout.

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  3. okay, I found your Vref. I also see that you have the bases of both BJT's shorted together. I put a cut between them and now it's completely dead. IMO, there must be an error somewhere else too.

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    1. That cut is definitely missing. My bad.

      The first buffer has its own voltage divider, which is 1K8 + 22K in the schematic - it's 9K1 + 22K on Dirk's FC10/LM7 schem. That would be one place the look. I suspect that with 1K8, the base of Q1 is getting way too high voltage. Other thing that i'm not 100% sure is the 1M at the JFET gate. That could go either tpo ground of vref. Probably it should go to ground...

      Other than those, i can't spot anything at the moment. Dirk's schem is at his site:
      http://www.dirk-hendrik.com/temp/ibanez_fatcat_la_metal.pdf - I has only couple minor changes to BS10, which has a schem up on FSB, drawn by Bernarduur.
      +m

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  4. fixed it. I found the other error. YAY! i'll post the corrections in a few minutes.

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    1. Letmeknowletmeknow!!! That'll mean that the same errors are on the FC10 and LM7 layouts too :) I'm at work, so i'll be able to fix the layout(s) in about 7 hours...
      +m

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    2. okay, here's the fix! add that cut, reverse the leads on the drive pot and move the lower link to this location as shown in the diagram below (the diagram shows ALL of the fixes). it works perfect now and sounds great.

      http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/IbanezBS10/MIROs-Ibanez-BS10-BassStack-corrected.png



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    3. Damn my typos. I'll be fixing the layout(s) today.

      Huge thanks to John!
      +m

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    4. So the crucial changes are:
      1. link should be at non-inverting input instead of inverting input
      2. the cut between the buffer bases

      I'm now quite confident that the 1M at the JFET gate needs to connect to ground. You should probably solder the bottom lead to one row higher.
      +m

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    5. How does it sound? I wasn't impressed with the demo, sort of undefined and woofy.

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    6. ...and of course the labels for dist/drive pot is in reverse...

      Now fixed. If there's nothing more than those three (four, if we count the 1M resistor) things, this could be tagged. It may also be that i'm missing something.... Let's just wait for John before i set the tag.

      It sounds exactly like it is. A Rat for bass.
      +m

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    7. yep. the schemo does show the 1M going to ground. I just relocated it and am going to test it now.

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    8. moved the lower leg of the 1M up to ground. works perfect. tag it verified.

      it sounds great and is not muddy, woofy, or undefined at all.

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  5. I am just wondering if I can sub the 5534DD. for TL072, 071, NE5532, JRC4558, LM308. 301, 386. If so which would you reccomend?

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    1. That is a single opamp, so any of those dual ones won't work.

      None of your singles have the compesation on the right pins (LM308 has it between pins 1 and 8, while 5534 has it between pins 5 and 8). So you'd really need to get 5534 or do some alterations to the board.
      +m

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  6. hey there, just beeing curious...is the layout at the top the final and working version or do i have to change anything as discribed.
    cheers

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    1. Latest with all fixes.
      +m

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    2. thanks. about done...;-) keep it up!!!

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